The huge rise in the price of stamps in April this year – and the fact that first- and second-class stamps no longer have the price printed on them – has made the cost of stamps one of the most commonly asked questions on google.co.uk.

After stamps, it's the cost of passports, MOTs and 0844 numbers we're most interested in. Switch the computer to look only at questions from Google users in the US, and you find that while Americans are just as keen to seek out the cost of stamps, after that it's the cost of dental implants, living in Hawaii and abortions. In Ireland, on google.ie, the first autocomplete suggestion for "what is the cost of …" is "living in Australia" – which may say something about Ireland's unemployment crisis. Mind you, it's also the sixth most common "what is the cost of …" question in the UK.

First-class stamps, for all of those asking, shot up from 46p to 60p on 30 April, while second-class stamps jumped from 36p to 50p.

The good news is that when it comes to passports, the cost actually came down this week, with new rates effective from 3 September. A standard 32-page passport sent by post within around three weeks now costs £72.50 for an adult, down from £77.50, and £46, down from £49, for a child aged under 16. There are faster but pricer services – the one-week Fast Track service costs £103 for an adult and £87 for a child, while passports obtained via the one-day Premium service cost £128 for an adult and £106.50 for a child. The Fast Track and Premium services are not available for first-time applicants.

The current MOT test fees are: £54.85 for cars (with up to eight passenger seats), £29.65 for motorbikes and £37.80 for motorbikes with a sidecar. JP/PC

How save Google image Photograph: Graphic

Next month SSE, one of the biggest utility companies, with 5m electricity and 3m gas customers, will raise prices, again, this time by 9%. Fears are growing that the other suppliers will follow suit. So it's perhaps not surprising that gas bills are the most common search question when it comes to saving money.

Your first step should be to cut the amount of energy you are using. Go to energysavingtrust.org.uk for a free, and comprehensive, home energy check. You'll get a full report with all the details of your home's energy use and the savings you could make. Its helpline is on 0300 123 1234.

Simple measures are best: turn the thermostat down by 1C and you'll cut heating bills by up to 10%, saving the typical household around £50 per year. Insulating the loft (at least 270mm deep) can save another £100.

Switching suppliers is always a good idea, but choose your time carefully – the "big six" energy companies tend to follow each other's price movements. There's no point in switching, then facing a price hike at the new supplier. See if you can save money with the Guardian's switching service, or call 0800 634 3874.

The next most sought-after money saving advice on Google is about food, which again reflects recent steep price rises. Consumer group Which? says its number one tip to shoppers is to skip the luxuries, such as a coffee shop stop-off. Buy in bulk, check prices on mySupermarket.co.uk, try cheaper cuts of meat, make (and grow) your own, switch to own brands.

And is your Sky bill busting your budget? It now costs £500 a year if you want the sports channels on top of the basic package, which is steep when you consider you get the whole of the BBC for £145.50. PC

Do shops Goggle image Photograph: Graphic

Most consumers are still befuddled about their rights, judging by the questions they tap into Google. Refunds are the most vexing issue, and unfortunately there is no straightforward answer.

Shoppers' basic statutory rights are enshrined in the Sale of Goods Act of 1979. But ultimately what happens is dependent on individual circumstances.

Goods bought from a shop must be fit for purpose, match any description given and be of satisfactory quality. If these requirements are not met, you may have a legal right to reject them and get your money back.

If you cannot get back to the shop for some days, you should telephone and let the seller know you have a problem with the goods. Usually the right to reject is about three to four weeks from the date of sale, not the date of inspection. After that, in most cases you have lost the right to reject. Legally, you have a "reasonable" time to use or inspect goods. The problem is that there is no legal definition of what "reasonable" is. You don't have to have a receipt – usually a proof of purchase is satisfactory.

You have no right to take the goods back simply because you have changed your mind. Many shops do have a returns policy, but there is no legal obligation to provide one.

The next most popular question on Google, about displaying prices, is more straightforward. The law requires mainstream retailers to display prices, including VAT, and to be "clearly legible". Items do not have to be individually priced (they can use a price list) but the price should be available so that the customer does not have to ask for it.

Shops don't have to accept £50 notes. Banknotes are "legal tender" – but that doesn't mean anyone has to accept them. RS

Where cheap Google image Photograph: Graphic

Only one thing seems to beat the UK consumer's obsession with finding the cheapest iPad or iPhone: it's finding cheap flights and holidays. Tap "where can I find the cheapest …" into google.co.uk, and you'll discover that four of the 10 most commonly asked questions are about Apple products. But holidays trump the lot.

For flights the reality is that almost nothing touches Ryanair for cheapness – but critics say nothing touches it for grimness either. But try skyscanner.net to capture all the deals from airlines heading to your destination. Fly on Tuesdays or Wednesdays – it can be half the price of flying on Friday. And split the outbound and return between different airlines – few are cheapest both there and back.

The latest painful rise in train fares has made finding cheap tickets a top search on Google. Money's top tip has always been to split your ticket. Don't buy a ticket for an entire long-distance journey. Split the journey up – without having to get off the train – and you can save a fortune. And explore "carnets" of 10 tickets which offer great value if you make a few journeys a week.

The surprise entry in the top 10 of most-asked questions in this category on Google, however, is "where can I find the cheapest Vans shoes?", which even comes ahead of people searching for cheap iPhones. Maybe it's the £45 price tag for what are essentially plimsolls that sets people off searching … but without much success. PC

How much Google image Photograph: Graphic

Forget that doggy in the window. When you type the words "how much is" into Google, it reveals that the two things preoccupying us the most are the value of our car and our house (bearing in mind our obsession with property prices, some may be surprised it's in that order).

If you want to know how much your car is worth, try Glass's, the "UK's leading motoring guide". Type in a few details (you have to register) and it will give you a price range.

Sites such as webuyanycar.com will also offer up a value, though you need to know things like your mileage, previous owners and service history. Parkers is good for used cars.

When it comes to houses, there are plenty of websites. Rightmove's vast database means it is always worth a look. It will throw up homes currently on the market that match your criteria, plus details of past sales. FindaProperty.com will give you a free estimated market value "based on various data sources", though the ranges tend to be quite wide. Just put in your postcode. Similarly, Zoopla give a free estimate.

If you really want to know how much your home is worth, ask two or three estate agents. Then take the average of what they say. But they will be gunning for your business, so watch out if you're not serious.

Stamps and passports we have covered elsewhere, while child benefit is paid to all households with children at £20.30 a week for the eldest, or only, child, and £13.40 a week for each younger sibling.

The ninth most popular "how much is … a cup" – might seem odd. We think it's to do with British cooks puzzling over "cups" used as measures in American recipes. RJ